This application discloses claims and embodiments generally related to an apparatus for treating domestic waste and sewage produced from a residential dwelling.
A residential dwelling possesses a plumbing system for providing water service and removal of domestic and other aqueous waste. In an urban setting, the waste system is connected to the centralized waste system operated by a municipality or city, which receives discharged domestic waste and waste water for treatment and/or collection. In a rural setting, centralized waste water and treatment systems or plants are not feasible or provided. Therefore, on-site waste water treatment and management must be provided to dispose of domestic waste and/or remediate water for use.
Domestic waste generally comprises a mixture of waste solids and water in varying proportions. In on-site systems, the disposal system water is separated from the organic solids. The waste water may be discharged into the local environment. The solid materials may be treated and decomposed within an on-site system. Any remaining untreated or otherwise non-disposable solid waste materials must be hauled off-site for disposal and/or treatment.
A variety of devices and apparatuses have been attempted for collecting and treating on-site domestic waste and sewage produced from a residential dwelling. One common approach is a septic treatment system. A septic treatment system generally includes a septic tank that receives the domestic waste water influent from the residential dwelling. The waste is held quiescently in the tank, permitting most of the solids to settle in the bottom of the tank. The partially clarified water may then be discharged onto the surround property. However, the water effluent still contains some dissolved and entrained solids, and is not sufficiently safe to discharge to surface water(s). Usually, the water effluent is discharged to a leach field and routed into a field of permeable pipes or conduit buried below the surface. The water effluent permeates the walls of the pipe or conduit and into the surrounding subsoil. Any waste remaining in the water effluent is entrained in the surrounding subsoil and gradually decomposed by indigenous soil organisms. The water effluent percolates downward, eventually joining the local ground water table.
However, a leach field may be implemented only where the soil is sufficiently permeable to allow the water effluent to percolate therethrough. Thus, shallow soils, including thin soil layers with bedrock close to the surface, or soils with high clay content, are often not sufficiently permeable and are generally unsuitable for a septic tank system of this type.
Generally, waste solids accumulate in the bottom of a septic tank, and the rate of decomposition is slower than the rate of accumulation because the anaerobic bacteria that consume solid waste are inefficient in consuming the waste material. The serial build-up of non-decomposed solid waste may be pathogenic and cause illness among residents or visitors to the dwelling. Thus, periodic removal and disposal of the accumulated waste must be performed.
Another type of system includes an aerobic activated sludge process. The process usually comprises an apparatus with two chambers. The first chamber has a mixed aqueous slurry of active aerobic bacteria, called activated sludge. Aerobic conditions are maintained in the activated sludge by injecting air by one of several means known in the art. The domestic waste influent is added into and mixed with the activated sludge. Aerobic bacteria absorb and decompose the entrained and dissolved solids in the domestic waste.
A small purge stream exits from the first chamber and into a second chamber with quiescent conditions. The sludge mass in the slurry settles to the bottom of the second chamber while the separated water exits. The activated sludge solids settle faster than the raw solids in domestic waste, so the aqueous effluent from an aerobic treatment apparatus is usually clarified sufficiently to discharge directly to a surface water body. The settled sludge is also non-pathogenic and can be more easily discard, such as implementation of the discard into land-farming.
The aerobic process is more efficient than the anaerobic process, but has a higher initial cost because of the powered machinery required to operate the aeration process. In addition, the cost is increased because of the electricity required to operate the machinery and the periodic maintenance of the machinery.
Another example of devices used for treating domestic waste is composting toilets and waste composting units. Composting decomposes organic solids with aerobic bacteria in a solid mass or pile with little free excess water, as opposed to a slurry or fluid system. In a composting system, the waste pile (devoid of excess free water) has many small voids or pores through which air can circulate allowing oxygen to communicate with the aerobic organisms in the central volumes of the waste pile. The aerobic organisms digest and metabolize waste, reducing its volume and producing more environmentally compatible humus as a final waste product that is more easily disposed.
Accordingly, certain embodiments of the invention represent improvements in the bio-composting of domestic waste through use of a treatment apparatus as disclosed herein.